the body’s directions

Wednesday, March 1, 2017

Another evening in the world of sport and another round of players being helped off the court. Last night, it was Kevin Durant with a medial collateral ligament sprain and worry that because of mechanism of injury, his anterior cruciate, the ACL, might be torn. Anterior, posterior, medial, lateral, the directions of the body can be a mystery, even to those inside the medical community. North, south, east, west, up, down don’t exist in medicine.

The body’s road map has many different directions. and it all starts with the anatomic positon, best illustrated by Da Vinci’s Vitruvian Man and the basic coordinate   :

  • The heart is the center of the body. Move away from the heart and you’re going distal, move closer to the heart, you’re now more proximal. The wrist is distal to the elbow, but the elbow is proximal to the wrist.
  • The front of the body is anterior and the back is posterior. But it’s important to look at Da Vinci’s man because the hands are a special case that we’ll visit in a bit.
  • Draw a line from the nose to the belly button and that is the midline. Move away from the midline and you’re lateral; move closer to the midline and you’re now The ear is lateral to the cheek and the nose is medial to the eye.
  • Up and down don’t exist. You’re either moving cephalad towards the top of head or caudad towards the bottom or the tail.

The anatomy directions are standard stuff and don’t change regardless of whether the patient is standing, sitting or lying flat. But some parts of the body have special directions.

The hand is special perhaps because its function is so important to the way the body works. Look again at how Da Vinci lines up his man. The arms are at the side with the palms facing forward. That can be confusing because the little finger, what many people consider the outside of the hand is really medial and the thumb is lateral. To avoid any confusion, directions in the hand are different.

  • The anterior hand is called the palmar surface and the back of the hand is called the dorsum.
  • The radius and ulna are the two bones in the forearm that connect to the wrist. The thumb is on the radius side and the little finger on the ulna. The midline of the hand runs from the tip of the middle finger to the wrist and stuff is described as either radial or ulnar. The index finger is ulnar to the middle finger but medial to the thumb.
  • Each finger has three joints named by the bones that meet at each (the thumb only has two), metacarpophalageal joint (MCP), proximal interphalangeal joint (PIP)and distal interphalangeal joint (DIP). Describing the fingernail, it is located on the dorsum of the finger, distal to the DIP joint.

The abdomen is divided into quadrants, the neck has zones, the eye has chambers, the foot has a plantar surface (the sole). There are special terms for most body parts that become the foreign language that is medicine and anatomy.

It’s important to understand the body’s directions to help people understand, through words, the geography of the body, and to help explain to one another where stuff is happening. For Mr. Durant and his MCL injury, the medial collateral ligament runs from the femur to the tibia on the medial part of the knee. If you tried to explain it as the inside part, that might be confusing because the MCL is not located inside the knee joint, but instead it is outside the joint towards the midline of the body.

Direction terminology is especially important when health professionals talk to each other so that can help visualize the body and the description of an injury, rash, lump or bump. East and west is good for maps but not for arms and legs, while up and down works for elevators. But in the medical world, using the same language makes good things happen.


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knee ligament sprains

Tuesday, September 29, 2015

Writing about injuries is not always easy when relying on press releases, sports stories and snippets of interviews. Sometimes, the story falls in your lap. The Steelers’ Ben Rothlisberger gets hit, hurts his knee, hobbles off the field and by morning has an MRI confirming a medial collateral ligament tear…prognosis 4-6 weeks before return to play. Sometimes, though, there needs to be detective work because the information is more opaque. The NHL is a constant frustration with their upper body/lower body injury mantra.

But it’s Lionel Messi’s knee injury that posed a challenge. His team FC Barcelona tweeted that “Messi has a tear in the internal collateral ligament of his left knee. He will be out for around 7-8 weeks.” It seems relatively transparent and open, telling the world and especially Barca fans about Messi’s injury. The only problem is that the knee doesn’t have an internal collateral ligament, so tearing it is a little problematic. The challenge then, is to sort out the real injury.

Clue one is provided by photos of the injury. As he lay on the ground, Mr. Messi reaches down and rubs the inside part of his left knee.


Clue two is that the recovery time is measured in weeks, not months.

Clue three is that no surgery is planned. Argentina national team doctor, Donato Villani, was quoted by the Argentine paper, Ole: “The injury was to the ligament on the inner part of the knee, a ligament that is extra-articular, that obviously suffers injury like any other ligament, but this one is outside the joint. He avoided a valgus force injury of the joint; it is not a tear that needs surgery.”

As it turns out, the knee joint has four ligaments that provide it support and stability. The anterior and posterior cruciate ligaments prevent the knee from sliding forward and backward, while the medial and collateral ligaments prevent side to side motion. This allows the knee to do what it’s supposed to do, flex and extend, like a hinge. Each ligament has the potential to be torn and the treatment approach is different for each.

It’s important to remember that a torn ligament is called a sprain. Grade 1 sprains describe a ligament whose fibers have been stretch and a grade 2 sprain happens when the fibers are partially torn. A grade 3 sprain occurs when the ligament has been completely torn.

In athletes, each knee ligament has its own treatment, healing and return to play time frame.

  • Anterior cruciate ligament tears almost always need surgery and recovery time is measured in many months.
  • Posterior cruciate ligaments may not need surgery but rehabilitation may take 3 months or more to return range of motion, stability and strength. For those with a PCL tear who undergo surgery, the rehab time may stretch to 9-12 months.
  • Medial collateral ligament tears used to be treated with surgery but non operative treatment is found to be more successful. Grade 1 and 2 sprains often heal well enough in 1-2 weeks to allow return to play while a grade 3 sprain may need 6 weeks or longer. While early return to play is allowed, the MCL continued to heal for many more months. Surgery may be required if there is recurrent injury or chronic instability.
  • Lateral collateral ligaments tend to heal less well than the MCL and it completely torn, the LCL injury may also involve damage to the posterolateral corner of the knee. This is a group of structures that provide knee stability (and include the fibular collateral ligament, the popliteofibular ligament, the mid-third lateral capsular ligament, the biceps femoris head and the lateral gastrocnemius tendon and the IT band). A grade 3 tears often needs surgery and rehab time that can last a year.

Mr. Messi had an “internal” ligament injury that does not need surgery and will heal in 7-8 weeks. The medial collateral ligament fits that description but the clincher is that the medical collateral ligament has fibers that are both external (outside of) and internal to the joint. While it is a thick band of tissue that covers the whole of the m3edial or inner side of the knee, there are many layers that are outside of the knee joint and others that are internal to the joint. That division is based upon the capsule that is the boundary of the joint itself.

Medical commentary by proxy can be harrowing but sometimes, understanding anatomy, injury patterns and treatment options can uncover the mysteries that are contained in press releases and twitter feeds. And at the end of the day Ben Roethlisberger and Lionel Messi are related by MCL sprain.


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